Bur for treating grindstones.



E. MLHALL.

BUR FOR TREATING GRINDSTONES.

APPL lCATl0N Hum 05c. 28. 1915.

1,219,299. Patented. M211: 191?. V

UNITED ED ARD 1:. Banner calmness, amw YORK.

mjm "r assume om ss ons.

, Specification of ,flattersfatent.

Application filed December as, 1915. ser l No. 68,977.

To allwhomz't'may someway i Be it known that I, EDWARD M. HALL, a citizen of the; United States, residing at Carthage, in the "county of Jefferson-and State ofNew York, have invented new and useful Improvements in Burs for Treating I *Grindstoneg'of which the following is a specification.

It is my object to provide a'bur 'for treating the surface ofwood-pulp grindstones, so constructed that, when used by unskilled laborers, the surface of the stone will, with certainty, be properly treated, and without danger of injury to the grindstone. It has been the custom to treat grindstones with a rotating bur pressed firmly against, and moved across, the-surface of the stone. As

' the grindstone rotates, a rotary motion is imparted to the bur, the teeth of which biteinto the surface of the stone and, by the move ment of the bur across the stone, produce therein depressions, corresponding in shape and dimensionsto the teeth of the bur. A

bur commonly used is provided with trans-- .verse, diagonally-disposed V- shaped teeth, separated by similar 'V-shaped channels which produces in the face of the stone .cor-

respondiugly-shaped teeth and depressions.

A grindstone having a surface of thatcharacter is poorly adapted for the production of a uniform quality of wood fiber, for the reason that the sharp pointed teeth at first produce a considerable percentage of very ,short length fiber and sawdust, and, after: the stone has been in use for some time, the

teeth are broken down unevenly, and when in this condition the stone produces a small percentage of uniform'fibers, the result is that a stone provided with sharp, 'V-shap'ed teeth cannot produce woodpulp containing a sutlicient percentage offfiber of that degree" ()fllnlfolllllily best suited for the manufactare-of news print paper and the careless use of such a bar mayr'esult in serious injury to'the stone. The most desired surface for a grindstone is one in which dBPIGSSlOIlS, .diagonally-disposed from side to side across the stone, are 'separatedgby flat-top ridges,

channels,

constituting the abrasive surfaces .which 'Serye to teer off the fiber from the \voodf Iii-IS difficult, however, ifvnot inipossible,to

use a b'urof the character described to produce such desired surface.

invention consists in a bur ,having transverse V-shaped teeth, separated by Patented Friar. 13,191'i.

the bottoms of which are substan- A t 1ally flat and serve not only to definitely limit the depth to which the teeth will be -drivenintothe stone to produce the dethe bottoms of which constitute the perip.h--

4 eral surface of the bur, and hence are sub "stantiallyfiat.

Such a bur may be used by an unskilled laborer witholltany danger of injury to the stone, and with the certainty of producing in the stonc'the desired surfaceand always- )roducin a ,definite uniform )att-ern. the l s bottoms of the channels 3 on the bur serving to limit the depth of thedepressions cutby the teeth 2, and at the same time to obtain the flat-topridgesin 'the stone between the depressions, I

- I clann as my nvention;

A bur for-use in treatingthe surface of,

grindstones, having teeth upon'its peripheral surface, said teeth being separated by channels, the bottoms-of which are substan- 'tially fiat and which. serve to limit the depth to which said-teeth maybe driven into the surface of the grindstone EDWARD M. HALL.

and to secure al'-- ternate flat-top ridges. 

